Develop Reference

Call void method from another method in the same class

At first my main problem was at how to call a method from the same class, even tough I think I found a way to do this, it's not working as I expected, and I would like to know what would be the best approach to my case.
This is the code I'm working on:
public class EscolhaAtendimento extends AppCompatActivity {
private ViewPager mSlideViewPager;
private LinearLayout mDotLayout;
String TAG = "TasksSample";
private TextView[] mDots;
private SliderAdapter sliderAdapter;
Dialog myDialog;
#Override
public void onCreate (Bundle SavedInstanceState){
super.onCreate(SavedInstanceState);
setContentView(R.layout.escolha_atendimento);
mSlideViewPager = findViewById(R.id.slideViewPager);
mDotLayout = findViewById(R.id.dotsLayout);
sliderAdapter = new SliderAdapter(this);
mSlideViewPager.setAdapter(sliderAdapter);
addDotsIndicator(0);
mSlideViewPager.addOnPageChangeListener(viewListener);
myDialog = new Dialog(this);
}
public void addDotsIndicator(int position){
mDots = new TextView[8];
mDotLayout.removeAllViews();
for (int i= 0; i < mDots.length; i++){
mDots[i] = new TextView(this);
mDots[i].setText(Html.fromHtml("•"));
mDots[i].setTextSize(35);
mDots[i].setTextColor(getResources().getColor(R.color.colorTransparentWhite));
mDotLayout.addView(mDots[i]);
}
if (mDots.length > 0){
mDots[position].setTextColor(getResources().getColor(R.color.colorWhite));
}
}
ViewPager.OnPageChangeListener viewListener = new ViewPager.OnPageChangeListener(){
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected (int i) {
switch (i) {
case 0: {
myDialog.show();
}
addDotsIndicator(i);
}
}
#Override
public void onPageScrollStateChanged(int state) {
}
};
public void ShowPopup(View v) {
TextView txtclose;
//Button btnFollow;
myDialog.setContentView(R.layout.pop_upfinal);
txtclose = myDialog.findViewById(R.id.txtclose);
txtclose.setText("X");
//btnFollow = (Button) myDialog.findViewById(R.id.btnfollow);
txtclose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myDialog.dismiss();
}
});
myDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
myDialog.show();
}
}
This class is an activity that on user swipe, the text and image from the buttons will change, even though their IDs will stay the same. (That's controlled by another class, it's working well).
Now, I wanted the image button on the activity do something different depending on which page is selected, and that's why there is a initial switch on the onPageSelected method, inside the Page change listener. The image button in the layout has the android:onClick="ShowPopup" tag, and I guess that also complicates things for me, if I wanted it to do something different in that same activity? Also, calling it that way on the switch, every time I change pages, and go back to the first one the popup window will open, since my call is explicit there. (As I said, even tough I found a way to somehow call my method, or at least it's result, it's not working as I expected).
Edit
I tried then changing it like this, so that the button wouldn't rely on the android:onClick="ShowPopup" Tag, and also wouldn't need to call a void method directly on the switch:
Added
public ImageButton popupchoice;
And also this to onCreate method:
popupchoice = this.findViewById(R.id.imgslide1);
Inside the switch I called it like this to get the button ID:
popupchoice.setOnClickListener(image1);
And set the View.OnClickListener like this:
View.OnClickListener image1 = new View.OnClickListener() {
public void onClick(View v) {
TextView txtclose;
//Button btnFollow;
myDialog.setContentView(R.layout.pop_upfinal);
txtclose = myDialog.findViewById(R.id.txtclose);
txtclose.setText("X");
//btnFollow = (Button) myDialog.findViewById(R.id.btnfollow);
txtclose.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myDialog.dismiss();
}
});
myDialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
myDialog.show();
}
};
But that returns me:
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference at .EscolhaAtendimento$1.onPageSelected(EscolhaAtendimento.java:81) Line 81 is the one inside the switch with the popupchoice.setOnClickListener(image1).
This error happens on page change, when coming back to the first Page, and also the button click won't work anymore.

I think you can use
EscolhaAtendimento.this.ShowPopup from inside your switch.

How to disable button in RecyclerView and from AsyncTask

I am trying to disable button after click in RecyclerView from Retrofit response.
Application is using RecyclerView to populate list and I am using Retrofit to communicate to back-end REST API. There are two buttons inside one item and Retrofit client is activated on click. And if response from API is successful button should be disabled. I came across on two problems:
first few items works just fine, but after few scrolls buttons I have never clicked on are disabled also;
second was that little few random buttons further on in list are still clickable.
public void onBindViewHolder(final NewsViewHolder holder, int position) {
holder.btnPositive.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// init Retrofit Client
JSONPlaceHolderAPI mAPIService;
mAPIService = ApiUtils.getAPIServiceFetch();
mAPIService.getNews(url).enqueue(new Callback<Result>() {
#Override
public void onResponse(Call<Result> call, Response<Result>
response) {
holder.btnPositive.setVisibility(View.GONE);
}
}
#Override
public void onFailure(Call<Result> call, Throwable t) {
// do code
}
});
}
});
holder.btnNegative.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
JSONPlaceHolderAPI mAPIService;
mAPIService = ApiUtils.getAPIServiceFetch();
mAPIService.getNews(url).enqueue(new Callback<Result>() {
#Override
public void onResponse(Call<Result> call, Response<Result>
response) {
holder.btnNegative.setEnabled(false);
}
}
#Override
public void onFailure(Call<Result> call, Throwable t) {
// do code
}
});
}
});
}
I suppose problem is somewhere in Retrofit where it uses background threads or AsyncTask.

This happens as the recycler view recycles(as the name suggests) the view that is visible to you and gives the same set of ids to every set of items which causes this problem .
This problem has 2 solution :
1) Stop the recycle behaviour of recyclerview as follows:-
#Override
public void onBindViewHolder(#NonNull MyViewHolder myViewHolder, int i) {
myViewHolder.setIsRecyclable(false);
}
But i strongly deny to use this cause recycling is reason why we use recyclerview.
2) Using a POJO Class:-
The best solution for it is to use a POJO class which will have two variables the first one is value and the second one is a boolean variable which show is the item disabled or not . Set the value of POJO boolean variable to true for the items u want to disable and in onBindViewHolder method only disable the buttons for the items which has false set in boolean variable .
If you still are confused contact me i will send you an example of it .

You need to hold states of those buttons. You can hold states in items(such as isNegativeEnabled, willPositiveDisplay etc.) of the list that populates recyclerview. When you click positive button, change willPositiveDisplay to false.
list[position].willPositiveDisplay = false;
And check list[position].willPositiveDisplay is true set visibility as visible, if not set as gone. And do this for negative button.

android rotating screen causes text colour to change to default

In my android app where I am creating a tic tac toe game, I have this code below where if it's player one move then set their selection as X with a particular colour, else it must be player 2 so set text as O for their selection with a different colour.
#Override
public void onClick(View v) {
if (!((Button) v).getText().toString().equals("")) {
return;
}
if (playerOneMove) {
((Button) v).setText("X");
((Button) v).setTextColor(Color.parseColor("#e8e5e5"));
} else {
((Button) v).setText("O");
((Button) v).setTextColor(Color.parseColor("#737374"));
}
...
}
I have a problem though and it is in regards to when I rotate the screen. When I rotate the screen, the text for X and O both change to the default text colour android studio provides. I want to keep the colours for these text but I am not sure how to do that? I have made sure there is no global text colour set.
Below is my code that handles orientation changes:
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putBoolean("playerOneMove", playerOneMove);
}
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
playerOneMove = savedInstanceState.getBoolean("playerOneMove");
}

You need to save the colours of each box of your tic tac toe board and retain them again on your layout configuration changes (i.e. device rotation).
You might consider looking into the answer here for a detailed explanation of your problem. You might check the developer documentation here for handling the configuration changes as well.
The key idea is to save the layout statues in variables which survives the configuration changes and update them accordingly in your onCreate or onCreateView function in case of Activity and Fragment respectively. However, in your case, you need to store a lot of data and on each configuration change, you need to restore them again which is not an efficient way to do that. I would like to recommend you look for other available options which survive the orientation or configuration changes of your layout.
I would strongly suggest implementing ViewModel in your case, which survives the application configuration change and handles the overall UI representation in the most effective way. The idea is to bind your UI elements with your ViewModel and then retain the UI elements each time from your ViewModel. It can be retained at the exact state until the Activity or Fragment finishes.
In your case, I would like to provide an example of how you can prepare a ViewModel. Let us consider your ViewModel is GameModel which saves the layout items of your board.
public class GameModel extends ViewModel {
public final LiveData<Game> gameLiveData = new LiveData<>();
public GameModel() {
// trigger game load.
}
void doAction() {
// depending on the action, do necessary business logic calls and update the gameLiveData.
}
}
public class Game {
public static final int CROSS = 1;
public static final int ZERO = 0;
public int pos1 = -1; // Default values are -1, when the position is yet to be played
public int pos2 = -1;
public int pos3 = -1;
public int pos4 = -1;
public int pos5 = -1;
public int pos6 = -1;
public int pos7 = -1;
public int pos8 = -1;
public int pos9 = -1;
}
Now from your Activity, you need to add an observer to your GameModel class to update the UI accordingly.
public class UserActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.game_activity_layout);
final GameModel viewModel = ViewModelProviders.of(this).get(GameModel.class);
viewModel.gameLiveData.observer(this, new Observer() {
#Override
public void onChanged(#Nullable Game gameData) {
// update ui.
}
});
findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Pass parameters in doAction function to set the items in the Game class and update the ui accordingly inside the onChanged function.
viewModel.doAction();
}
});
}
}
Hope that helps!

Refresh adapter in a Fragment after DialogFragment dbflow insert

I have an activity that has 3 fragments on it with Tabs, one of them is called "TaskFragment".
In my main Activity i only load the fragments.
In TaskFragment i have a RecyclerView that is working fine and is showing the items as intended.
The problem comes, when i insert data using a DialogFragment, because it does insert data (i am using DbFlow ORM), but it does not (of course) refresh the adapter since it is in the TaskFragment fragment inside the DetailMainActivity activity as i said.
I have tried to use onResume() and onPause() in order to refresh the adapter, but they are never called since the activity does not get paused or in onresume for a DialogFragment.
I have tried aswell to use an interface, but it does not work and i have searched all over stackoverflow and google with no luck.
I leave here some of my code for you to understand better:
DetailMainActivity.java
Here in the onClick interface i show the DialogFragment to the user to input the information.
FragmentManager fm = getSupportFragmentManager();
AddSimpleTask sptask = new AddSimpleTask();
sptask.show(fm, "tag");
TaskFragment.java
In this fragment i have my RecyclerView
private void setupRecyclerView() {
mRecyclerView.setAdapter(adapter);
mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 2));
mRecyclerView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (DetailMainActivity.FAB_Status) {
DetailMainActivity.hideFAB();
DetailMainActivity.FAB_Status = false;
}
return false;
}
});
}
private void setupAdapter() {
adapter = new DetailMainTaskAdapter(simpleTaskList, this);
}
AddSimpleTask
And this is my DialogFragment. I have set a setOnShowListener() in order to avoid the DialogFragment to get dismiss early.
#Override
public void onShow(DialogInterface dialogInterface) {
final AlertDialog dialog =(AlertDialog) getDialog();
if (dialog != null){
Button positiveButton = dialog.getButton(Dialog.BUTTON_POSITIVE);
Button negativeButton = dialog.getButton(Dialog.BUTTON_NEGATIVE);
positiveButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (mEditTextName.getText().toString().trim().isEmpty() ||
mEditTextContent.getText().toString().trim().isEmpty() ) {
if (mEditTextName.getText().toString().trim().isEmpty()) {
mEditTextName.setError("Can not be empty");
}
if (mEditTextContent.getText().toString().trim().isEmpty()) {
mEditTextContent.setError("Can not be empty");
}
}else {
presenter.beingInsertion(mEditTextName.getText().toString().trim(), mEditTextContent.getText().toString().trim()
, foreignId);
}
}
});
negativeButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dismiss();
}
});
}
}
If the insert is successfully achieved the onInsertSuccess method is called (i am using MVP)
#Override
public void onInsertSuccess() {
Snackbar.make(getActivity().findViewById(R.id.containerMainDetail), "Actividad agregada", Snackbar.LENGTH_SHORT).show();
dismiss();
}
I have called adapter.notifyDataSetChanged() in many places, and i also tried with a custom interface, but i can not make this work.
Sorry for the long post, but thanks in advance for your help.

There are some errors in your statement but I'll get to that later. notifyDataSetChanged() only notifies the adapter that the underlying list (or array) has changed. The implication is that you first need to requery your database and obtain the new list before calling notifyDataSetChanged() on the adapter else there is no point as the underlying list will still be the same and it will not update the adapter.
The correct way of calling this will be through your custom listener interface and not in the onPause()/onResume() callbacks as there is the possibility that the user does not enter a value and hence you will unnecessarily be querying the database. In your custom listener interface implementation, first update the list with the new data from the DB and then notify the adapter.
Which leads to the error in assumption that onPause()/onResume() callbacks do not happen when your Activity is covered by a DialogFragment - this is incorrect. The moment the activity view is even partially covered, the onPause() callback is triggered.

Not propagating clicks

When I click an Android button the Android's Software Keys are shown (hidden before) instead of firing the onClick() method for the actual button that I click.
I have two methods for showing or hiding the system UI:
1.
// Set up the user interaction to manually show or hide the system UI.
contentView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (TOGGLE_ON_CLICK) {
mSystemUiHider.toggle();
} else {
mSystemUiHider.show();
}
}
});
and 2:
/**
* Touch listener to use for in-layout UI controls to delay hiding the
* system UI. This is to prevent the jarring behavior of controls going away
* while interacting with activity UI.
*/
View.OnTouchListener mDelayHideTouchListener = new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
if (AUTO_HIDE) {
delayedHide(AUTO_HIDE_DELAY_MILLIS);
}
return false;
}
};
And I also have another method which a switch to get the onClick() event on buttons
public void onClick(View v) { switch() { } }
Is it possible to fix this behaviour and when I click the actual button will be fired and the System UI will be shown?

There is no workaround to overcome this behaviour until you have both touch listener and also a click listener inside the same view. Try using
View.SYSTEM_UI_FLAG_LOW_PROFILE|View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
instead. Add the below code before setcontentview() method.
View decorView = getWindow().getDecorView();
int uiOptions = View.SYSTEM_UI_FLAG_LOW_PROFILE|View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;
decorView.setSystemUiVisibility(uiOptions);